It isn't a stencil, though the majority of the shapes on it are standard ones that are already available within the app. The two that aren't are the jigsaw-like pieces that look as though they should interlock (2nd row down). To create these you need OmniGraffle 4 Pro and to use the combine/substract shapes options (you create the left hand shape by combining a circle and rectangle, and the right hand by subtracting the circle from the rectangle).